Palestinian farmers harvest olive trees on the outskirts of the West Bank village of Salem, near the Jewish settlement of Elone Moreh, on Oct. 12.

By Lawahez Jabari, NBC News

SALEH, West Bank — Every fall, hundreds of thousands of Palestinians take to the fields to participate in the annual olive harvest, a celebrated national event. Children take time off school and adults skip work to rise at sunrise and walk through the groves echoing with the sound of sticks striking olive branches.

Not only is the olive tree an important symbol of Palestinian identity and culture, the olive oil sector is important to the Palestinian economy and supports around 80,000 families. But the centuries-old tradition is under threat.

"There have been cases of arson and tree uprooting by the settlers," Hamdan Hamdan, who has farmed land in the village of Saleh, a West Bank community with a population of 6,000, told NBC News. "Usually settlers stop us from accessing the trees, just this morning they scared off farmers who crossed beyond the bypass road to their fields."

Most countries consider settlements Israel has built in territory Israel captured in a 1967 Middle East war to be illegal under international law. Israeli Prime Minister Benjamin Netanyahu, a longtime supporter of the settlers, has agreed to a limited freeze on construction but refused U.S. administration appeals to extend it. The issue helped scupper 2010 peace talks.

According to the United Nations, around 40 percent of the West Bank is effectively off limits to Palestinians or access is highly restricted.

Settlements, outposts, bypass roads and military bases and 73 barrier gates in the West Bank prevent olive farmers from reaching their groves, the report said. The restricted access and alleged constant intimidation has made regular orchard and tree maintenance unfeasible for many locals.

Village chief Netham Shteyeh told NBC News that the settlement of Elon Moreh was built on 500 dunums of land (1 acre equals 4 dunums) confiscated from the village.

"And now our village is encircled by a bypass road. This gate here is locked all-year round except for several days during the olive harvest," he told NBC News. "Last year they opened it for four days and this year nine. This means 1,000 dunums of our best land is now isolated."

The pressure and intimidation are constant, he said.

"We have been beaten by settlers and soldiers in the past attempting to cross the bypass road," Shteyeh said.

Abed Omar Qusini / Reuters

Israeli soldiers stand guard as Palestinians, sitting on the back of a tractor-driven cart, make their way to harvest olive trees on the outskirts of Salem.

When presented with allegations that settlers and members of the military had harassed and intimidated Palestinian farmers, the Israeli Army told NBC News that they were taking "every measure to ensure the safety and security of the local residents in Judea and Samaria (the West Bank), while persistently combating terror and protecting the residents of the State of Israel."

Activists rally around harvestsThe tensions surrounding the annual harvest have made it a magnet for activists who support the Palestinian cause.

Alaa Badarneh / EPA

Palestinians harvest olive trees on the outskirts of Salem on Oct. 12.

"I go olive harvesting to resist the occupation," said Maria Baff, a 26-year-old from Germany who has attended five harvests over the years. "I want to help farmers in achieving their rights to harvest and to protect them from the occupation, from settler violence, from their inability to access their land mainly due to the army, as well as restrictions of access to water, crop (and) tree uprooting and agricultural vandalism."

But it is not all politics for Baff and others.

"It’s also a fun activity working together and learning new cultures," she said.

But Baff said she had seen no improvements to the situation faced by farmers despite official assurances and international pressure.

"You might have a few more permits here and there, a few more opened gates here and there, but they face the same problem as five years ago," she told NBC News.